Proposed research concerns the development of practical procedures for short-term and long-term banking of granulocytes effective for hematologic support of leucopenic patients is a continuation of our long-range program. Using our centrifugal elutriation method for isolation of pure granulocytes, we will test the following new approaches to improve granulocyte preservation such as: (1) Maintaining cells in a resting metabolic state by lactate inhibition of phosphofructokinase. (2) Maintaining intracellular levels of nucleotides (ATP and cyclic AMP). Restoration of nucleotides intracellularly by means of liposomes or glycerol will be studied. (3) Macromolecular plasma substitutes will be used in place of serum proteins in preservation medium. (4) Reduction of granulocyte damage due to intracellular release of lysosomal enzymes by lysosomal membrane stabilizers and/or enzyme inhibitors. (5) Regeneration of -SH groups of cells by sulfhydryl compounds after preservation. (6) Modification of granulocyte membrane lipids by increasing proportion of saturated lipids using liposomes. Also, we will investigate effects of various gels for stabilizing cell suspension during storage. Furthermore, we will examine several recent claims of successful recovery of human granulocytes after cryopreservation and will adopt any repeatable effective procedure as a base for improvement. Animal model, using rabbits, will be developed for testing in vivo granulocyte function.